Distance-Dependent Electronic Interactions Across DNA Base Pairs: Charge Transport, Exciton Coupling, and Energy Transfer

The -stacked bases of B-DNA constitute a helical ruler present nowhere else in nature. When two chromophores are placed at the ends of a base-pair domain with fixed orientations of their transition dipole moments, insertion of an additional base pair between the chromophores increases the distance between the chromophores by ca. 3.4 angstrom and the angle between their transition dipoles by ca. 36 degrees. The consequences of these changes on the dynamics and efficiency of photoinduced charge transport and upon exciton-coupled circular dichroism and fluorescence resonance energy transfer are discussed.